Linear-tracking windshield wiper system for wiping a rectangular field

Abstract

A system for wiping a windshield of a vehicle in a rectangular field, comprising a wiper arm, a wiper blade assembly operationally attached to the wiper arm, and means for rotating and translating the wiper arm to cause said wiper blade assembly to track in a linear path across the windshield. The system includes a three-gear train for moving a pivot point on the wiper arm along a circular path centered on a virtual pivot point. The system is especially suited for wiping low aspect ratio windshields.

Description

TECHNICAL FIELD [0001] The present invention relates to means for wiping fluids from surfaces; more particularly, to wiping means including a blade for wiping-moisture from vehicle windows; and most particularly, to a system for providing linear-tracking motion of a wiper arm and associated wiper blade to wipe a rectangular field on a vehicle window. BACKGROUND OF THE INVENTION [0002] Wiper systems for wiping moisture from vehicle windows are well known. A typical wiper system includes an oscillating motor that moves a wiper arm and attached wiper blade through a wiping arc of between about 90° and 180°. The wiping pattern produced by the blade is an arcuate area bounded on the ends by the extremes of blade travel and on the outer and inner edges by the radii of travel of the outer and inner tips of the wiper blade. It is a necessary consequence of a prior art oscillating system that window areas outside the wiping pattern are not wiped. Where the aspect ratio (defined herein as the...

AI Technical Summary

Benefits of technology

[0014] In a second embodiment, a pivot element is provided for supporting a wiper arm, slidably and pivotably disposed on the pivot element, such that the wiper arm can simultaneously rotate about the pivot axis and slide past the pivot axis during oscillation. The inner end of the wiper arm supports a roller that travels in a first cam groove formed in a plate supporting the pivot element. The cam groove guides the inner end along a curved path that causes the wiper arm to be simultaneously pivoted about the pivot axis and translated past the pivot axis such that the outer end of the wiper arm, extending over the windshield, describes a straight line across the windshield. A slotted actuation arm is attached to an oscillatory motor, the slot engaging a pin at the arm inner end to drive the inner end rotationally about the motor axis at a varying radius dictated by the cam groove. As in the first embodiment, to maintain a constant vertical attitude of a wiper blade assembly attached to the outer end of the wiper arm and extending over the windshield, a parallel attitude control arm connects the wiper blade assembly to a tab at the inner end of the wiper arm. The rotational speed of the oscillatory motor may be varied to vary the translational speed of the wiper blade assembly.

[0015] In a third and currently preferred embodiment, a rack portion of a ring gear is fixed to a mounting plate as a first gear in a three-gear train. A second gear is driven along the first gear in a first circular path by a motor having a rotor attached to the second gear and a stator disposed in an arcuate track coaxial with the ring gear. A third gear supports a wiper arm and is urged along a second circular path coaxial with the ring gear and motor track, the axis of the third gear defining the inner pivot point of the wiper arm, and the motion of the wiper arm being identical to that provided by a pivoting link as shown in the '369 patent. Advantages of this embodiment over the '369 mechanism are that the central pivot, pivoting link, and vertical track are all eliminated. The result is a relatively compact apparatus having a minimal vertical space requirement, requiring no pivot point on the windshield surface, and easily disposable within the tailgate of a sport utility or hatchback vehicle.

Problems solved by technology

Prior art arcuate wiping patterns on vehicle rear windshields are annoying and dangerous to the operators of these and other vehicles.

Whether by road spatter, vehicle exhaust, rain, or snow, during vehicle use under adverse road conditions the non-wiped areas rapidly become opaque and useless to a vehicle operator in seeing other vehicles to the rear or which may be attempting to pass.

To keep non-wiped areas useful in such conditions, a vehicle operator must stop frequently and clean those non-wiped areas by hand; in practice, most drivers simply ignore those areas and drive with decreased rear-windshield visibility, at increased hazard to themselves, their passengers, and the occupants of other vehicles.

None of these inventions purports to sweep a fully rectangular area of a windshield, however.

A drawback of this invention, however, is that it is useful over only relatively small angles of wiper arm oscillation.

Depending upon the size and shape of the windshield, the fixed pivot point may be geometrically required to be on the windshield itself when the included angle is still less than 90°, a practical impossibility.

When the included angle is 120°, as is desirable for wiping of a low aspect ratio windshield, the fixed pivot point is centered on the linear tracking line of the free end of the wiper arm, a clearly impractical situation.

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